My mac mini (less then a year old) has been shutting off on its own and won't start by pressing the power button. I have to unplug it and plug it back in, then it turns on and runs normal. Not sure how long it takes to shut off. I don't think any of us changed some settings that would cause this. It did however, just start doing this after we bought and installed a new laser printer (HP laser jet P1102w) and a Samsung disc drive. Can't see how that should have caused it either. Any help would be much appreciated.